Synthesis and characterization of a new trifunctional magnetic-photoluminescent-oxygen-sensing nanomaterial

Magnetic Fe(2)O(3) nanoparticles coated with SiO(2) chemically doped with a Ru(II) complex were prepared using a simple solution based method. Field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) showed that the Fe(2)O(3) nanoparticles with a mean diameter of ～115?nm were successfully coated with Ru(II) complex-chemically doped SiO(2) shell with a thickness of ～30?nm. The obtained nanocomposite material showed a strong magnetic response to a varying magnetic field, exhibited the bright red triplet metal-to-ligand charge transfer ((3)MLCT) emission, and its photoluminescent intensity was sensitive to oxygen concentration. Compared with the Ru(II) complex in silica gels, the Ru(II) complex in the magnetic-optical-oxygen-sensing nanocomposite demonstrated improved thermodynamic stability of emissions. These nanocomposites are also nontoxic and easily conjugated with biomolecules. Their magnetic, photoluminescent and oxygen-sensing properties make them promising candidates for cell separation, biomarkers and optical oxygen sensors, which can measure the O(2) concentration in biological bodies.